1. Field of the Invention
The present invention relates to mobile radio communication terminals, and in particular, to a device and method for automatically disconnecting a call after completion of a telephone conversation.
2. Description of the Related Art
In general, a mobile radio communication terminal, such as a cellular telephone, holds a speech path until a user inputs (or presses) a call end key, even though the other party""s communication terminal ends the call.
FIG. 1 illustrates a block diagram of a common mobile radio communication terminal. Referring to FIG. 1, a controller 10, a one-chip microprocessor, controls the overall operations of the mobile radio communication terminal. A memory 20 permanently stores an operating program and temporarily stores data generated during execution of the operating program. A key input part 30, (i.e., a keypad), includes a plurality of numeric keys and a function key, and generates key data for the respective keys. A display 40 displays the key data input from the keypad 30, and the operating status of the mobile radio communication terminal in text and icons. An RF (Radio Frequency) part 50 converts an RF signal received via an antenna ANT to an IF (Intermediate Frequency) signal, and an IF signal to be transmitted to an RF signal. An audio part 60 demodulates an output signal of the RF part 50 to output an audio signal through a speaker SP, and modulates an audio signal input from a microphone MIC to send the modulated audio signal through the RF part 50 and the antenna ANT.
FIG. 3 is a flowchart illustrating a conventional method for disconnecting a call after completion of a telephone conversation in the mobile radio communication terminal of FIG. 1. Referring to FIG. 3, the controller 10 determines whether a speech path is formed in response to a SEND key input from the key input part 30 or an incoming call received through the antenna ANT (step 201). If the speech path is formed, the controller 10 proceeds to set the mobile radio communication terminal to a call state and transmits/receives an audio signal through the audio part 60 and the RF part 50 (step 203). In the meantime, controller 10 determines whether an END key (i.e., call end key) is input from the key input part 30 (step 205). If the END key is input, the controller 10 disconnects the speech path to terminate the call (step 207).
However, controller 10 continues to hold the call state of step 203 unless the user presses the END key, even though the other party ends the call. Therefore, the user is required to press the END key without fail in order to disconnect the speech path, which creates an additional distraction to the user, particularly when he drives.
It is therefore an object of the present invention to provide a device and method for automatically disconnecting a call after completion of a telephone conversation, even without pressing a call end key.
To achieve the above object, there is provided a device for automatically disconnecting a call after completion of a telephone conversation in a mobile radio communication terminal. A speaker signal detector generates a first detection signal upon detection of an audio signal received from an other party, and a microphone signal detector generates a second detection signal upon detection of an audio signal input from a microphone. A controller disconnects an established speech path when the first and second detection signals are not input from the speaker signal detector and the microphone signal detector, for a predetermined time.